1. Field of the Invention
This invention relates to sheet handling machines, for instance machines that handle sheets of paper and articles of similar sheet-like materials in plain and/or folded form.
2. Prior Art and Other Considerations
In paper handling, for example for mass-mailing purposes, it is often needful and advantageous to produce, handle, and convey various paper articles (imprinted or plain) through machines in parallel. For instance, paper from a roll of continuous paper, while being unrolled, may be cut off transversally and slit longitudinally into side-by-side parallel sheets for further handling. In another example, larger sheets need be slit into halves along a line that is in line with the transport direction while sheets are being conveyed. In this respect for instance, larger sheets may be transversally folded in a folding machine, and the folded sheet may be slit into two folded articles along a line parallel with the transport direction. Thereafter, the two side-by-side parallel articles need to be conveyed to further handling and utilization equipment.
In such handling in general, the need arises to separate the paper articles from one another laterally in order to facilitate further independent handling and to avoid mutual interference of adjoining lateral edges. Moreover, it is necessary and advantageous in most such situations to separate these articles in a manner assuring parallel alignment, absence of skew, and definite transverse displacement locations subsequent to their separation operation to facilitate further handling.
Whereas lateral offset or displacement motions during conveying have been employed in sheet paper article handling in the past, such motions obtainable with conventionally utilized mechanisms have not been entirely satisfactory in situations requiring parallel lateral displacements while achieving specific positional alignments. Conventionally utilized mechanisms have provided lateral article displacements without being capable of assuring absence of significant skewing motions. Consequently, article realignment subsequent to its displacement had to be performed. Such realignment or reorienting has mostly relied on forcing the article onto and along a registration rail.
For example, so-called cross-carriers are known for shifting of paper articles laterally (with respect to their conveying motion) against a registration rail to obtain alignment therewith. Such cross carriers generally employ a plurality of long cylindrical rollers or flat belts upon which the articles are conveyed. These rollers or belts are tilted and angled to gradually move articles against and then along a registration rail in the direction of their conveying motion. Generally, the articles are held down upon the rollers or belts by freely revolving idler balls to assure attainment of the desired registration alignment and to avoid skewing due to friction effects along the rails. It will be appreciated that motions of articles are not exactly repeatable in such arrangements, particularly due to retarding friction along the rails.
Moreover, paper articles having an adverse edge aspect ratio, i.e. having short lateral edges in relationship to the length of the edges directed along the direction of the main conveying motion, are difficult, if not impossible, to align with a stationary registration rail and keep aligned therewith while sliding therealong. Such paper articles, rather than becoming reliably and repeatably aligned along the rail, tend to skew further, and even tend to tumble over onto their longer edge along the rail under some circumstances.
The device of the present invention is intended to overcome the above-discussed difficulties and to provide for reliable and repeatable parallel paper article separation and alignment thereafter even (and particularly) for paper articles being handled and conveyed with an adverse edge aspect ratio.
An overall feature of the invention is the provision of a sheet separator device for transversely separating sheets being conveyed thereto and therethrough in a common plane in parallel side-by-side relationship, whereby the sheets are transversely displaced without incurring a significant skew and whereby the sheets reliably attain a repeatable alignment and transverse position.